Sexual Infections 'Epidemic' Sweeping Nation, CDC Reports

As lovers embraced on Valentine's Day, the Centers for Disease Control had just released a study on sexually transmitted infections that might have caused some to reconsider how they celebrated the day.

There are 20 million (both diagnosed and undiagnosed) new cases being spread each year in the nation, and Americans who are between 15 and 24 account for half of them, despite the fact that demographic comprises just a quarter of the population, according to the CDC.

"STIs take a big health and economic toll on men and women in the United States, especially our youth," CDC epidemiologist Catherine Lindsey Satterwhite, who led the study, told NBC News.

In 1996, the CDC reported 15 million cases and then 18.9 million in 2000. However, researchers said information gathering methods have changed since 1996, so there could be a discrepancy.

Human papillomavirus remains at the top of the list as the most common infection of 2013.

The CDC said 90 percent of HPV cases clear up naturally within two years. However, the infection has been shown to trigger the onset of cervical cancer, which is the third most common cancer for women.

On the infections list, HPV is followed by chlamydia, gonorrhea, syphilis, herpes, hepatitis B, and HIV.

The CDC warned in the new report that the U.S. was facing an "ongoing, severe STI epidemic."

The CDC estimated that the government spends $16 billion annually on healthcare costs associated with providing medical care for people with STIs. A significant portion of the $16 billion goes to treating patients with HIV/AIDS, who require medical care their entire lives.

The rise in STI cases may not be the only concern for people who are sexually active in the U.S.